Currency cassettes provide ATMs with a source of bank notes and are strong metal or plastic boxes comprising a lid releasably coupled to a body. One end of the body includes a covered aperture that is automatically opened when the cassette is inserted into a currency dispenser and automatically closed when the cassette is removed from the currency dispenser. The opposite end of the body includes a handle for carrying the cassette which also aids in insertion and removal of the cassette.
The use of a currency cassette in an ATM can be described with reference to FIG. 1 which shows a schematic side elevation view of a cash dispenser unit 73 of an ATM. The cash dispenser unit 73 holds a number of currency cassettes 89 each holding a stack of currency notes 68. Each cassette 89 holds only one denomination of currency notes, but different cassettes may contain different denominations. The notes 68 are held in place in the cassette by means of a pusher plate 69 which urges the stack of notes to one end of the cassette. It is necessary for the dispenser to detect automatically what currency is contained within each cassette. This is currently achieved by means of a pattern of magnets in the cassette which can be detected by the dispenser; cassettes with different denominations of notes having different patterns of magnets.
When one or more notes are to be dispensed from a particular cassette, the pick mechanism 74 associated with the cassette draws a note from the cassette such that its leading edge is gripped between drive rollers 90. The note is then fed along the feed path 72 by further drive rollers 92, through a retard mechanism 10 to the stacker wheel assembly 75. In operation, the stacker wheel assembly 75 rotates continuously in a counter-clockwise direction (for the arrangement shown in FIG. 1) and the note is fed into a compartment 81 formed between adjacent tines 78. If more than one note is to be dispensed, each note is fed into a successive compartment 81 as the stacker wheel assembly 75 rotates. Having completed half a rotation, the note is removed from the stacker wheel assembly 75 by fingers 94 of a stripper plate assembly 96 pivotally mounted on a shaft 98. Once removed from the stacker wheel, the note is placed on a belt 100 resting against the stripper plate assembly 96 and any subsequent notes which are to be dispensed simultaneously with the first note are placed on top of the first note to form a bundle 68′. When the required amount of notes (which may be just one note) have been assembled into the bundle 68′, a pair of belts 102 (only one of which is shown in FIG. 1) is rotated on a shaft 104 such that the bundle 68′ is trapped between the belts 100, 102. The bundle is then fed between belts 100, 102, 106, 108 through a note exit slot 110 in the housing 112 of the cash dispenser unit 73 to a position where the bundle 68′ can be collected by the user of the ATM. If a multiple feeding is detected in the course of stacking the bundle of notes 68′ or one or more of the notes is rejected for any reason, the bundle is not fed to the note exit slot 110. Instead the stripper plate assembly 96 is pivoted into a position as shown by the dashed outline 96′ and the belts 100, 102 are operated in the reverse direction to deposit the bundle 68′ into a reject note container 114 via an opening 116.
In order to detect when a cassette is about to run out of notes, a cassette is equipped with a “notes low” sensing system comprising a magnet located in the pusher plate 69 and a Reed switch located in the end of the cassette 89 near the pick mechanism 74. When the magnet in the pusher plate 69 gets close to the Reed switch it causes the contacts to close and the “notes low” situation is sensed.
Several problems exist with known currency cassettes. Firstly, if the cassette is not fitted correctly into the dispenser, the dispenser may detect an incorrect pattern of magnets and therefore incorrectly identify the denomination of currency in the cassette. This may result in incorrect amounts of money being dispensed by the ATM. Incorrect fitting of the cassette may also cause repeated failures of the pick mechanism.
Another problem is that the “notes low” sensing system is very variable and inaccurate. This causes problems in scheduling replacement/refilling of currency cassettes and can lead to dispensers running out of notes unexpectedly. Additionally, where an ATM has a low level of usage, an operator may choose to operate with cassettes which are never filled to capacity but instead are only filled with a few hundred notes each time. This may result in the operator permanently experiencing a “notes low” situation such that the sensing system is useless and the operator cannot determine when to replenish cassettes to avoid running empty.
The invention seeks to provide an improved sensing system and sensing method for media cassettes.